[Skip to Content]
[Skip to Content Landing]
Other Articles
May 28, 1938


JAMA. 1938;110(22):1831-1837. doi:10.1001/jama.1938.62790220006011

Some fifteen years ago several investigators in animal nutrition began to suspect that for normal reproduction the rat required a dietary constituent not yet recognized or included within the generally accepted group of accessories. At first there was some hesitation in accepting yet another member into the already large family of vitamins, but convincing evidence from various laboratories, especially from that of Evans and his co-workers, soon established the fact that when reared on diets otherwise complete, but not containing this new fat-soluble factor, rats did not have offspring, although they appeared to be quite normal in other respects. Male animals became infertile through degeneration of the germinal epithelium and the damage was irreparable. Females failed to carry their young to term; the embryos died and were absorbed, but the female reproductive mechanism as such was not damaged, since adequate dosages of the missing factor restored fertility. Still other experiments